Apple intros iPhone 4 at WWDC 2010, available June 24

As expected, Apple today announced the next iteration of their popular iPhone smartphone. Simply dubbed iPhone 4, the device introduces some new design elements like an integrated antenna system in the form of a stainless steel band that goes around the device, a flattened glass-like back for better reception, and a new high resolution "Retina Display". The latter is able to fit 326 pixels per inch of its surface, which is beyond the display capabilities of the human retina, and obviously a marked improvement over the 3GS -- or any other smartphone -- in both brightness and clarity.

The new display is 960 by 640 pixels, with an 800-to-1 contrast ratio. Like the iPad, it also has an LCD screen with IPS technology for superior viewing angles. Most of the specs we're already familiar with from previous leaks: A4 chip, larger battery, front-facing camera, micro SIM tray, 5-megapixel camera and LED flash on the back, noise cancellation mic, among other things. But Apple also threw in a new three-axis gyroscope, which paired with the iPhone's accelerometer and compass will offer six axis orientation for gaming and much more precise movement.

The camera on the back has been fitted with a backside illuminated sensor for low light photos, and besides capturing still images it can also record 720p high-definition video at 30fps. Users will be able to edit their videos with a mobile version of iMovie which will be available for $4.99 in the App Store. Also on the software side, Apple renamed its mobile operating system iOS 4 to reflect its spread to the iPod and iPad, announced iBooks for the iPhone, touted its iAds advertising platform, and unveiled its video calling software (Wi-Fi only for now) dubbed FaceTime.

Apple's iOS 4 will be free to all 3GS, 3G, and iPod Touch 2nd generation users on June 21st. As for the new iPhone 4, pre-orders start June 15 for the 16GB ($199) and 32GB ($299) models, with the phones available in stores roughly one week later on June 24. Besides the United States, Apple will launch the new iPhone in Germany, UK, France and Japan.